With Governors Ball rapidly approaching, as well as a slew of other nationwide music fests lined up this summer, now's the time to get into the workout groove. We mean, not only do you want to keep your butt looking perky in those denim cut-offs, you also want to make sure you've got enough stamina to stay dancing until every headliner's last song. And what better way to prep for festival season than with a few music-charged fitness classes that will have you rocking out while you sweat it out?